Perovskite ferroelectric ceramics with giant electrostrictive coefficient Q₃₃ have attracted much attention due to their high strain response with ultralow hysteresis. In this work, the electrostrictive properties as well as domain morphology of the lead-free (1−x)NaNbO₃-xBaTiO₃ (NN-xBT) (0.10 ≤ x ≤ 0.27) system were investigated systematically. A composition-insensitive Q₃₃ of 0.0406 m⁴/C² is identified in the NN-xBT ceramics (0.15 ≤ x ≤ 0.27). An ab initio computation indicates that transverse Q₁₂ would play an important role in understanding of the composition-insensitive Q₃₃. Furthermore, distinctively banding domains and inhomogeneous distribution of nanodomains were observed in NN-xBT by piezoresponse force microscopy. A continuous decrease of domain wall density was identified with respect to the increase of x. This study would not only deepen our understanding of the origin of composition-insensitive Q₃₃ in NN-BT and other related systems, but also provide a way to enhance the Q₃₃, i.e., by forming the solid solutions with end members, which possess high Q₁₂.

具有高电致伸缩系数Q _33的钙钛矿铁电陶瓷因其高应变响应和超低滞后性而备受关注。在这项工作中，电致伸缩特性以及无铅（1-域形态X）的NaNbO ₃ - X的BaTiO ₃（N，N- X BT）（0.10≤  X  ≤0.27）系统进行了系统的研究。一种组合物不敏感的Q ₃₃的0.0406米⁴ / C ²被识别在N，N- X BT陶瓷（0.15≤  X  ≤0.27）。一个从头计算表明，横向Q ₁₂在理解不敏感成分的Q ₃₃中将起重要作用。此外，通过压电响应力显微镜在NN- x BT中观察到明显的带状结构域和纳米结构域的不均匀分布。相对于x的增加，确定了畴壁密度的连续降低。这项研究不仅将加深我们对NN-BT和其他相关系统中对成分不敏感的Q ₃₃起源的理解，而且还将提供增强Q _33的方法，即通过与具有高Q _12的端基形成固溶体。